dnsdist arm32 build warning

[Habbie]

dnsdist-cache.cc: In member function ‘uint64_t DNSDistPacketCache::dump(int)’:
dnsdist-cache.cc:456:269: warning: format ‘%llu’ expects argument of type ‘long long unsigned int’, but argument 9 has type ‘time_t {aka long int}’ [-Wformat=]
         fprintf(fp, "%s %" PRId64 " %s ; key %" PRIu32 ", length %" PRIu16 ", tcp %d, added %" PRIu64 "\n", value.qname.toString().c_str(), static_cast<int64_t>(value.validity - now), QType(value.qtype).getName().c_str(), entry.first, value.len, value.tcp, value.added);

[chbruyand]

@Habbie do you still have your box anywhere so I could test the PR ?

[Habbie]

Box is gone but I can test this - waiting for Travis to be happy first.